A $7,000 camera probably qualifies are "prosumer", right?
I can't really think of anything else that could drive demand for 10TB drives. Even a single 4TB drive represents an absolutely mind-boggling quantity of compressed x.264 video. Uncompressed BD images, maybe, for the tiny percentage of people who know how to extra files from them. And backups, I guess.
But I couldn't even guess at how to quantify 10TB as audio recordings or still images in the way that retail hard drive packages most often do. Coming soon, the Seagate Gigantio: "Every noise you will ever hear in your entire life, stored in 128kb .MP3"